1. Field of the Invention
This invention relates to a speed reducer of high reduction ratio, and particularly concerns to a speed reducer improved so as to decrease its thickness dimension.
2. Description of the Prior Art
In a robot technology these days for example, a speed reducer has been provided with an electric motor to develop its speed into decreased rotation which is applied to a transfer arm. A speed reducer of this kind so far introduced are known as worm wheel reducer, a cyclo reducer, a harmonic drive reducer and the like.
However, a speed reducer particularly employed to robot technology is desired to satisfy the following advantages (i).about.(V) upon securing a controlling precision. That is, (i) High reduction ratio with compact structure, (ii) High controlling precision with least play such as backlash action. (iii) Elevated rigidity with high meshing rate. (IV) Improved controllability with relatively small inertia force at rotary members. (V) Least loss of torque with minimum wear.
The prior art reducers previously mentioned have had more or less disadvantages, so that a speed reducer which satisfies all the advantages (i).about.(V) is yet forthcoming.
Therefore, this invention has for its object to provide a novel reducer which satisfies all the advantages above so as to reply requests from the robot technology circle.
It is first object of the invention to provide a speed reducer structure which is capable of securing relatively high reduction ratio with compact construction.
It is second object of the invention to provide a speed reducer structure which is capable of eliminating a play such as backlash for high control precision.
It is third object of the invention to provide a speed reducer structure which is capable of securing improved rigidity with high meshing rate.
It is fourth object of the invention to provide a speed reducer structure which needs relatively small inertia force for rotary members to insure high controllability.
It is fifth object of the invention to provide a speed reducer structure which needs minimum loss of torque with least quantity of wear.